Particle size distribution of organic compounds in aqueous aerosols collected from above sewage aeration tanks

Abstract

Several classes of organic compounds were analyzed in aqueous aerosols collected in June, November, and December 1996 from above the sewage aeration tanks of a treatment plant (Prato, Italy). Particle size distribution of organic compounds and their enrichment ratio (E(r)) with respect to the magnesium ion were determined to infer the extent to which various species were aerosolized. Organic components were found to be predominantly enriched in fine and large particles of the aerosol and their transfer may be attributed to the 1) adsorption of surfactant organic matter at the air/water interface (such phenomenon is particularly evident for the free and ultra-fine fractions) and 2) flotation of colloidal matter from wastewater to the largest particles with consequent transport of the adsorbed organic compounds. In addition, the interaction of surfactants with hydrophobic compounds explained the enrichment of the latter in the finest fractions.